💧ClO2 has several industrial applications in water treatment
Clean drinking water
ClO2 in potable water treatment dates back to 1994 and has since been widely accepted as a versatile, effective, and more environmentally friendly disinfecting alternative for various large-scale commercial applications. ClO2 disinfection helps to produce clean water with low turbidity through pre- and post-oxidation treatment. The pre-oxidation process removes algae, bacteria, etc., while post-oxidation treatment removes inorganic components like manganese and iron, pathogens (including chlorine-resistant ones like Giardia and Cryptosporidium), and reduces/prevents the production of trihalomethanes (THMs) and haloacetic acids (HAAs) that are not safe for consumption.
It also functions as a deodorizer and taste remover with a residual effect, remaining effective for longer periods of time. Fewer by-products are produced as only a small dose of ClO2 is necessary for effective treatment.
Excess ammonia in the water, from naturally-occurring processes and/or chloramine disinfection which involves adding ammonia to chlorine, can result in water quality degradation and nitrification—the process of nitrogen compounds, primarily ammonia, oxidizing to nitrate and nitrite. Chlorine dioxide, unlike chlorine, does not react with ammonia but rather the ammonia and nitrogen oxidizing bacteria, and can, therefore, in low dosages, combat episodes of nitrification that, if not treated, can result in increased nitrate and nitrite levels, bacterial regrowth even after disinfection, and reduced pH, alkaline, dissolved oxygen, and chloramine residuals. In the chloramine secondary disinfectant process, chlorine dioxide’s selective chemistry, which creates by-products that also combat ammonia and nitrogen oxidizing bacteria, helps to maintain chloramine residual levels for microbial protection.
Shared pools
Using chlorine dioxide for swimming pool disinfection generates no harmful by-products and can protect swimmers from many diseases by killing pathogens including bacteria, viruses, and fungi in the water and stopping algae growth on the walls. For example, chlorine dioxide can prevent pink eye (conjunctivitis), the most common eye infection from swimming and often called “swimming pool conjunctivitis,” from spreading. It is ideal for eliminating cryptosporidium, a diarrhea-inducing parasite that can still exist even in properly chlorinated pools, and for reducing exposure to toxic nitrogenous (chloramines) or carcinogenic organic residuals (trihalomethanes) and HAAs. It also protects women from gynecologic diseases caused by different types of bacterial infections. Babies and those with sensitive skin similarly benefit from reduced irritation, especially when swimming in public pools.
Aquaculture
Often used within aquaculture and commercial aquaria, fishponds, and fish tanks in pet stores, supermarkets, and restaurants, ClO2 water purification helps maintain high water quality and keep fish healthy and active by removing negative water components and preventing disease. The more powerful the oxidant, the more harmful it is for living organisms. With chlorine dioxide's low oxidation power (above oxygen but far below ozone), combined with its high oxidation capacity and absence of harmful byproducts, it is safe and easy to use in aquaculture and can even increase oxygen content in water. Consistent application of low concentration chlorine dioxide will result in the following: less bacterial problems, less water odor, less biofilm and algae formation on walls and pipes, better water quality, and healthier fish development.
Chlorine Dioxide
Chlorine dioxide is more effective than chlorine as a disinfectant against microorganisms, controls taste and odor better than chlorine, and forms fewer THMs and HAAs than chlorine. Chlorine dioxide does form chlorite and chlorate, though at negligible levels at monitored amounts. Traditionally requires on-site production.
Chlorine
Chlorine is effective against most microorganisms, leaves a residual in the distribution system, and is relatively easy to use in hypochlorite form. However, it can form DBPs when organic substances are present, may not be effective against Cryptosproidium, and can cause taste and odor problems.